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| Abstract |
- Symbiotic N₂-fixing tree species can accelerate ecosystem N dynamics through decomposition feedbacks via both direct and indirect pathways. Direct pathways include the production of readily decomposed leaf litter and increased N supply to decomposers, whereas indirect pathways include increased tissue N and altered detrital dynamics of non-fixing vegetation. To evaluate the relative importance of direct and indirect pathways, we compared 3-year decomposition and N dynamics of N₂-fixing red alder leaf litter (2.34% N) to both low-N (0.68% N) and high-N (1.21% N) litter of non-fixing Douglas-fir, and decomposed each litter source in four forests dominated by either red alder or Douglas-fir. We also used experimental N fertilization of decomposition plots to assess elevated N availability as a potential mechanism of N₂-fixer effects on litter mass loss and N dynamics. Direct effects of N₂-fixing red alder on decomposition occurred primarily as faster N release from red alder than Douglas-fir litter. Direct increases in N supply to decomposers via experimental N fertilization did not stimulate decomposition of either species litter. Fixed N indirectly influenced detrital dynamics by increasing Douglas-fir tissue and litter N concentrations, which accelerated litter N release without accelerating mass loss. By increasing soil N, tissue N, and the rate of N release from litter of non-fixers, we conclude that N₂-fixing vegetation can indirectly foster plant–soil feedbacks that contribute to the persistence of elevated N availability in terrestrial ecosystems.
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| Additional Information |
- description.provenance : Made available in DSpace on 2012-11-16T01:34:39Z (GMT). No. of bitstreams: 1
HibbsDavidForestryN2-FixingRedAlder.pdf: 376359 bytes, checksum: 4e6a2cbaef204a4962ae5b21fceaf73b (MD5)
Previous issue date: 2012-11
- description.provenance : Submitted by Deanne Bruner (deanne.bruner@oregonstate.edu) on 2012-11-16T00:40:23Z
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HibbsDavidForestryN2-FixingRedAlder.pdf: 376359 bytes, checksum: 4e6a2cbaef204a4962ae5b21fceaf73b (MD5)
- description.provenance : Approved for entry into archive by Deanne Bruner(deanne.bruner@oregonstate.edu) on 2012-11-16T01:34:39Z (GMT) No. of bitstreams: 1
HibbsDavidForestryN2-FixingRedAlder.pdf: 376359 bytes, checksum: 4e6a2cbaef204a4962ae5b21fceaf73b (MD5)
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